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Case Control Study
Copyright: ©Author(s) 2026. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial (CC BY-NC 4.0) license. No commercial re-use. See permissions. Published by Baishideng Publishing Group Inc.
World J Orthop. Mar 18, 2026; 17(3): 113562
Published online Mar 18, 2026. doi: 10.5312/wjo.v17.i3.113562
Characterizing posterior calcaneal spur fractures in insertional Achilles tendinopathy: A case control study
Kenichiro Nakajima
Kenichiro Nakajima, Center for Foot and Ankle Surgery, Department of Orthopedic Surgery, Yashio Central General Hospital, Yashio-shi, Saitama 340-0814, Japan
Author contributions: Nakajima K is the sole author who performed the research and prepared the manuscript.
Institutional review board statement: Ethical approval for this study was obtained from the Institutional Review Board of Yashio Central General Hospital (approval No. YIHCE2022-12).
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The author reports no relevant conflicts of interest for this article.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Data sharing statement: CT images of all patients included in this study are stored in the hospital’s medical records. The data presented in this manuscript are kept on the author’s personal computer and are available upon request.
Corresponding author: Kenichiro Nakajima, MD, Center for Foot and Ankle Surgery, Department of Orthopedic Surgery, Yashio Central General Hospital, 845 Minamikawasaki, Yashio-shi, Saitama, 340-0814 Japan. nakajimakenichiro@hotmail.co.jp
Received: August 29, 2025
Revised: October 9, 2025
Accepted: December 19, 2025
Published online: March 18, 2026
Processing time: 200 Days and 1.6 Hours
Abstract
BACKGROUND

Despite being common in clinical practice, posterior calcaneal spur fractures in insertional Achilles tendinopathy (IAT) remain poorly studied.

AIM

To investigate spur fractures in patients with IAT.

METHODS

Patients with IAT who underwent surgery at our institution were retrospectively evaluated. Demographics and spur length were compared between patients with and without spur fractures. The diagnostic cutoff value of spur length for predicting fracture was determined via the receiver operating characteristic curve analysis.

RESULTS

This study included 227 feet (59 females, 168 males). The mean age was 53.9 years, and the mean body mass index was 27.3. Spur fractures were observed in 87 cases (38.3%), including 11 of 59 females (18%) and 76 of 168 males (45%). Spur length was significantly greater in patients with spur fractures than in those without fractures (12.3 vs 5.7 mm, P < 0.001), whereas height, weight, and body mass index were comparable. The optimal cutoff value for spur length in predicting fracture was 9 mm (specificity: 0.857; sensitivity: 0.816; area under the curve: 0.902).

CONCLUSION

Spur fractures were present in 38.3% of feet with IAT, occurring more commonly in males. Spur length was significantly associated with fracture, with a 9-mm cutoff predicting spur fractures. Given their nature as stress fractures caused by sustained traction forces from the Achilles tendon, spur fractures may warrant surgical intervention.

Keywords: Achilles tendon; Diagnostic imaging; Pathology; Severity of illness index; Heel spur; Tendinitis; Computed tomography

Core Tip: Spur fractures were frequently identified in patients with insertional Achilles tendinopathy, more commonly among men. Cases with spur fractures had a longer mean spur length. A spur length of 9.0 mm demonstrated high sensitivity and specificity for predicting spur fractures. Spur fractures may require surgical intervention due to their nature as stress fractures caused by sustained traction forces from the Achilles tendon on the spur.